tastewar

After 20 years on the original cassette and chain on my Specialized Crossroads, I've been having some trouble shifting into a couple of oft used gears, so I ordered a replacement chain and cassette. I forget exactly what the original cassette was, but I got a new 14-32 because I figure I'm getting older and can probably use a little help, and it was a few bucks cheaper than a much closer replacement. Well, after installing, the upper jockey wheel on my rear derailleur, the original Shimano Exage LX 500, interferes with the largest sprocket when in the smallest chainring. Rings are, I believe, 28-38-48.

Can anyone help me find a reasonably priced derailleur that will handle these gears?

Thanks,
--Tom

tastewar

I might have noted that I do understand that this is a max of 38 teeth for wrap, and the big sprocket on back is a 32 (actually, I guess that is there already), and I believe those are the important specs, but it seems that retailers don't always list these capacities on the derailleurs they sell. Also, it's a 7-speed cassette, but I think it only matters that it isn't 10 speed.

Retro Grouch 

Look at your derailleur from the back. Do you see a little adjustment screw near where the derailleur attaches to the bike frame? Dial that screw in a ways and see if that solves your problem.

Al1943

You probably need to adjust the "B" screw. Check for adjustment instructions a www.parktool.com and at www.sheldonbrown.com.

tastewar

Thank you both -- I have tightened it all the way, and I might just squeak by with that. I'd been aware of that adjustment screw, but didn't really know what it could do for me before. Thanks for the education!

Al1943

It's possible to replace the "B" screw with a longer one. Some people install the "B" screw in backwards.

FastJake

+1

Exage LX is a "mountain" derailer right? I'd expect it to handle a 32T. I'd probably try a longer screw first.

But after 20 years, maybe you deserve a new RD You could probably pick up a new Deore model for not much money. Just make sure not to get a 10-speed MTB derailer because it won't work with your shifters.

tastewar

I gather that a longer B screw isn't something you go to the shop to pick up; just a longer screw with the right threads. Is that correct?

I can't say for certain about the Exage, though that would be my guess. It is a "cross" bike, but I've probably only added 3 or 4 teeth to the total wrap. The original cassette was prob. a 13-28, and the rings haven't changed, so it can handle 35 teeth; now it's being asked to do 38.

I appreciate the thought about deserving a new RD, but I'll probably stick with this one if I can (so far so good). Might get some new pedals for her, though, and fenders next...

bobotech

You might need to take a link or two off of the chain, did you measure the chain when installling the new chain?

tastewar

I was just reading up on chain sizing. I just eyeballed it when installing; will have to try again with a more exacting methodology.